Tribological characteristics of ultrahigh molecular weight polyethylene (UHMWPE) based compositions with graphite and molybdenum disulfide are studied under conditions of dry friction, boundary lubrication, and abrasive wear. It is shown that, under dry sliding friction, the wear rate of UHMWPE-graph ite and UHMWPE-MoS 2 polymer compositions is halved as compared to that of pure UHMWP, while their mechanical characteristics change only slightly. Under the conditions of abrasive wear, the wear resistance of these composites increases by 1.3-1.5 times. Concentrations of the fillers, which are optimum for improving the wear resistance, are determined. The supramolecular structure and the topography of worn surfaces of the UHMWPE compositions with various concentrations of the fillers are examined. A comparative analysis of the wear resistance of the composites under conditions of dry friction and lubrication is carried out. Mecha nisms of the wear of the UHMWPE-graphite and UHMWPE-MoS 2 polymer compositions under condi tions of dry sliding friction and abrasive wear are discussed.

In order to develop biocompatible antifriction composites based on UHMWPE the mechanical and tribotechnical characteristics of a hybrid polymer matrix in the form of a mixture (blend) of UHMWPE with polytetrafluoroethylene (PTFE) have been studied under dry friction, boundary lubrication, and abra sive wear. It has been shown that the wear rate of the material under dry sliding friction was reduced more than twofold compared with pure UHMWPE. However, the mechanical characteristics have changed insignifi cantly. Under the boundary lubrication (distilled water), the wear resistance of the matrix material is similar to that for dry sliding friction. Under abrasive wear, the durability of the composites differs a little from that for pure UHMWPE. The mechanisms of wear of the polymer blend UHMWPE-PTFE under dry sliding friction and abrasive wear have been discussed.

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Abstract. In order to compare effectiveness of adding solid lubricating fillers for polymeric composites based on ultrahigh molecular weight polyethylene (UHMWPE) with graphite, molybdenum disulfide and polytetrafluoroethylene, their tribotechnical characteristics under dry friction, boundary lubrication and abrasive wearing were investigated. The optimal weight fractions of fillers in terms of improving wear resistance have been determined. The supramolecular structure and topography of wear track surfaces of UHMWPE-based composites with different content of fillers have been studied.